Ultra high resolution flat panel display having in-cell type touch sensor

ABSTRACT

A display having a touch sensor comprises: a plurality of pixel areas disposed in a matrix manner on a substrate; a routing line running along a first direction on the substrate; a first passivation layer covering the routing line; a touch electrode covering the routing line and corresponding to a grouped pixel areas on the first passivation layer; a touch contact hole exposing some portions of the routing line by penetrating the touch electrode and the first passivation layer; a second passivation layer covering the touch electrode; a passivation contact hole exposing the touch contact hole and some portions of the touch electrode around the touch contact hole by penetrating the second passivation layer; and a touch terminal connecting the touch electrode and the routing line on the second passivation layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korea Patent Application No.10-2014-0194431 filed on Dec. 30, 2014, which is incorporated herein byreference for all purposes as if fully set forth herein.

BACKGROUND

1. Technical Field

The present disclosure relates to an ultra high resolution flat paneldisplay having an in-cell type touch sensor. Specifically, the presentdisclosure relates to an ultra high resolution flat panel display havingthe in-cell type touch sensor in which the parasitic capacitance betweenthe touch electrode and the routing line is reduced and the storagecapacitance between the common electrode and the pixel electrode can beensured enough.

2. Discussion of the Related Art

Recently, as increasing the needs for display representing the variousmultimedia data, the flat panel displays are developed in large areawith low price and high quality (high video quality, ultra highresolution, increased brightness, real color representation ability,etc.). These flat panel displays are equipped with various input devicesfor interfacing with the user, including keyboard, mouse, track-ball,joy-stick, digitizer, and so on.

However, the above mentioned input devices should have enough space forinstalling into the display and for working space. Further, sometimesthe users have to learn how to use these input devices. Therefore, easyand simple input devices for the display are required. One solution isthe touch sensor by which the user can input information directly on thescreen of the display with fingers or a touch pen while seeing thedisplay.

The touch sensor has less errors and simple structure. User can inputand/or select his/her instructions by simply touching the screen of thedisplay without any input devices, easily and quickly. With thiseasiness, the touch sensors are applied to the various display system.

According to the structure, a touch sensor can be categorized into theadd-on type, the on-cell type, and the integrated type (or in-celltype). In the add-on type touch sensitive display, the touch sensor isattached on the top surface of the display after the display and thetouch sensor are manufactured separately. In the on-cell type touchsensitive display, the elements for the touch sensor are formed on thetop substrate of the display, directly. In the in-cell type touchsensitive display the elements for the touch sensor are manufacturedinto the display panel. Therefore, the in-cell type can be much thinnerthan other types of touch sensitive displays and has a much longer lifetime and endurance.

Especially, for the in-cell type, since the common electrode of thedisplay pixels can be used as the touch electrode of the touch sensor,the thickness of the display having touch sensor can be thinner. As theelements for the touch sensors are formed into the display device, thetouch sensor can endure a large number of touch actions. Nowadays, thein-cell type is prevelant among the touch sensors embedded in displaysystems.

The in-cell type touch sensor can be categorized into the photo type andthe capacitance type in accordance with the sensing method. Further, thecapacitance type can be divided into the self capacitance type and themutual capacitance type.

The self capacitance type is that a plurality of patterns are formed atthe touch area and the variations of the capacitance of each pattern aredetected for deciding where the touch occurred. The mutual capacitancetype is one where a matrix type array of the X-axis electrodes and theY-axis electrodes are formed at the touch area, and the touch action canbe detected by applying the driving pulse to the X-axis electrode and bydetecting the variations of the voltage at the sensing nodes from theY-axis electrodes. The sensing nodes can be defined by the crossingpoint of the X-axis electrodes and the Y-axis electrodes.

However, for the mutual capacitance type touch sensor, the amount of themutual capacitance generated at sensing the touch is low, but theparasitic capacitances between the gate line and the date line includedinto the display are high. Therefore, it may be hard to exactly decidewhere the touch action is detected, due to the interference of theparasitic capacitance.

Further, for the multi touch sensing, the mutual capacitance type touchsensor should have a plurality of touch driving lines for touch drivingand a plurality of touch sensing lines for touch sensing on the commonelectrode. Therefore, the line structure would be very complicated.

Having the high touch resolution with the simple line structure, theself capacitance (type) touch sensor is more widely used than the mutualcapacitance touch sensor.

FIGS. 1 and 2, illustrate a liquid crystal display having the selfcapacitance touch sensor (or, ‘touch sensor embedded display’) accordingto the related art. FIG. 1 is a plane view illustrating the structure ofthe touch sensor embedded in a display according to the related art.FIG. 2 is a plane view illustrating the enlarged part having two touchelectrodes (Tx) denoted as {circle around (a)} in FIG. 1.

Referring to FIG. 1, the display having the self capacitance touchsensor has the display area AA and the non-display area (or ‘bezelarea’) NA. The display area AA is the area in which the touch electrodesused as the common electrode are formed and the video information isrepresented. The non-display area NA surrounding the display area AA isthe area in which various lines and the touch driving circuit IC areformed.

The display area AA includes a plurality of touch electrodes Tx arrayedalong to the first direction (for example, X-axis) and the seconddirection (for example Y-axis) crossing to the first direction, and aplurality of routing line TW along to the second direction. For example,the touch electrodes Tx may be arrayed in a matrix manner of N block×Mblock (N rows×M columns).

The plurality of touch electrodes Tx arrayed in the display area AA maybe formed by dividing the common electrode of the liquid crystaldisplay. During the display mode, for representing the video data, acommon electrode can work as the common electrode. During the touchdriving mode, for sensing touch action, the common electrode can work asthe touch electrode.

FIG. 2 illustrates an area where two neighboring touch electrodes Tx inthe vertical direction (the second direction, or Y-axis). At one touchelectrode Tx, a plurality of pixel area PA may be allocated. In FIG. 2,the nine pixel areas PA arrayed in a 3×3 matrix manner are allocated ateach touch electrode Tx. However, more pixel areas PA can be allocatedat each touch electrode Tx.

Any one pixel area PA is defined by the crossing structure of the gateline GL running along the first direction (or X-axis direction) and thedata line DL running along the second direction (or Y-axis). In thepixel area PA, main elements for the display are disposed. In theexample of the liquid crystal display of FIG. 2, a thin film transistorT connected to the gate line GL and the data line DL and the liquidcrystal cell LC driven by the thin film transistor T may be disposed.

In each pixel area PA, one pixel electrode PXL is disposed. The pixelelectrode PXL is connected to the thin film transistor T and is appliedwith a driving voltage corresponding to the video information via thedata line DL. For driving the liquid crystal cell LC by the drivingvoltage applied to the pixel electrode PXL, the common electrode COM isdisposed as facing the pixel electrode PXL. The common electrode COM maybe disposed in each pixel area PA individually. On the other hand, forthe driving stability of the liquid crystal cell LC, it is prefer thatthe common electrodes of all pixel areas are commonly connected.

When touch electrode Tx is formed, to simplify the structure, the touchelectrode Tx may be used as the common electrode COM. Here, each commonelectrode COM is formed as covering every 9 pixel areas PA. Further,these common electrodes are used as the touch electrode Tx.

All pixel areas PA are grouped into 3×3 matrix manners, each commonelectrode COM covering every 3×3 pixel areas PA can be designed as eachtouch electrode. For example, as shown in FIG. 2, the first commonelectrode covering the first group of 3×3 pixel areas PA can be definedas the 1row 1column touch electrode T11. The common electrode coveringthe right neighboring group of 3×3 pixel areas PA can be defined as the1row 2column touch electrode T12. The common electrode covering thelower side neighboring group of 3×3 pixel area PA can be defined as the2row 1coloumn touch electrode T21, and the common electrode covering thediagonal side neighboring group of 3×3 pixel area PA can be defined asthe 2row 2column touch electrode T22.

Each touch electrode Tx may have one routing line TW. For example, the1row 1column touch electrode T11 connects to the 1row 1column routingline TW11. The 2row 1column touch electrode T21 connects to the 2row1cloumn routing line TW21. The routing lines TW may be disposed asoverlapping with the data line DL with an insulating layerthere-between. Otherwise, the routing lines TW may be disposed at thesame layer with the data line DL with a predetermined distance from thedata line DL. In that case, the aperture ratio may be reduced.

The non-display area NA surrounds the display area AA and includes theintegrated circuit for data driving and touch driving IC and variouslines. The integrated circuit for data driving and touch driving ICdrives the gate lines GL, supplies the video data to the data line DLand supplies the common voltage to the touch electrode Tx (the commonelectrode) at the display mode. Further, during the touch mode, theintegrated circuit IC for data driving and touch driving supplies thetouch driving voltage to the touch electrode Tx. By scanning thevariations of the capacitance at the touch electrode Tx, it is decidedthat which touch electrode Tx is touched.

The various lines include the routing lines TW connected to each touchelectrode Tx and the gate lines GL and the data lines DL connected tothe integrated circuit for data driving and touch driving IC.

FIGS. 3 and 4 illustrate the connecting structure of the touch electrodeand the routing line in the liquid crystal display having the selfcapacitance touch sensor. FIG. 3 is a plan view illustrating an enlargedarea including two neighboring pixels denoted as {circle around (b)} inFIG. 2 according to the related art. FIG. 4 is a cross section view,along the cutting line I-I′ of FIG. 3, illustrating the structure of theliquid crystal display having the self capacitance touch sensoraccording to the related art.

Referring to FIGS. 3 and 4, the liquid crystal display having the selfcapacitance touch sensor according to the related art includes aplurality of pixel areas PA arrayed in a matrix manner by the crossingstructure of the gate line GL and the data line DL on the substrate SUB.Each of the pixel areas PA includes a thin film transistor T, a pixelelectrode PXL connected to the thin film transistor T, and a commonelectrode COM facing with the pixel electrode PXL.

The thin film transistor T may have the double gate structure in whichthe semiconductor layer is overlapped with the gate line GL twice sothat two channel areas A are formed. On the substrate SUB, a lightshielding layer LS may be formed where the channel area A is disposed.On the light shielding layer LS, a buffer layer BUF is deposited ascovering the whole surface of the substrate SUB. On the buffer layerBUF, a semiconductor layer is disposed where the light shielding layerLS is formed. On the semiconductor layer, a gate line GL and the gateelectrode G are disposed with a gate insulating layer GI.

One side of the semiconductor layer is connected to the date line DL.The semiconductor layer has a ‘U’ shape so as to cross the gate line GLtwice. The overlapped portion of the gate line GL with the semiconductorlayer would be the gate electrode G. The portions of the semiconductorlayer overlapped with the gate electrode G would be the channel area A.On the whole surface of the substrate SUB having the gate line GL andthe gate electrode G, an intermediate insulating layer IN is deposited.

On the intermediate insulating layer IN, data line DL is disposed. Oneportion of the data line DL is connected to the one side of thesemiconductor layer. The other side of the semiconductor layer isconnected to the drain electrode D. Here, the source electrode S is notformed separately but is defined as the portion of the data line DLoverlapped with the semiconductor layer. The drain electrode D may beformed separately. Otherwise, one portion of the pixel electrode PXLconnected to the other side of the semiconductor layer may be the drainelectrode D.

On the whole surface of the substrate SUB having the thin filmtransistor T including the gate electrode G, the source electrode S andthe drain electrode D, a planar layer PAC is deposited. On the planarlayer PAC, the common electrode COM is disposed. In order to be used asthe touch electrode Tx, the common electrode COM may be patterned ascovering the grouped pixel areas. Further, the common electrode COM,also being the touch electrode Tx, preferably has the open structure inwhich it does not cover the pixel contact hole PH exposing the drainelectrode D.

On the whole surface of the substrate SUB having the common electrodeCOM, a first passivation layer PAS1 is deposited. On the firstpassivation layer PAS1, a routing line TW (e.g., TW11) is formed. Inorder to ensure enough aperture ratios, the routing line TW ispreferably overlapped with the data line DL. On the whole surface of thesubstrate SUB having the routing line TW, a second passivation layerPAS2 is deposited. Each routing line TW is connected to one touchelectrode Tx. Therefore, by patterning the second passivation layer PAS2and the first passivation layer PAS1, the touch contact hole TH exposingone portion of the touch electrode Tx and the routing contact hole WHexposing one portions of the routing line TW are formed.

On the second passivation layer PAS2, the pixel electrode PXL is formed.The pixel electrode PXL connects to the drain electrode D of the thinfilm transistor T through the pixel contact hole PH. Within the pixelarea PA, the pixel electrode PXL is disposed as overlapping with thecommon electrode COM with the second passivation layer PAS2 and thefirst passivation layer PAS1 there-between. Here, using the samematerial with the pixel electrode PXL, the touch connecting terminal TTis formed. The touch connecting terminal TT electrically/physicallyconnects the touch electrode Tx exposed through the touch contact holeTH to the routing line TW exposed through the routing contact hole WH.

Like this, the routing line TW extends along to the second direction,e.g., Y axis. Therefore, any one routing line TW may overlap with thetouch electrodes Tx arrayed along the Y-axis. For example, 2row 1columnrouting line TW21 connects to the 2row 1column touch electrode Tx21 andoverlaps with other touch electrodes Tx arrayed at lower side from the2row 1column touch electrode Tx21 along to the Y-axis with the firstpassivation layer PAS1 there-between.

When the parasitic capacitance between the 2row 1column routing lineTW21 and other touch electrodes Tx, the sensing accuracy may be lowered.Therefore, it is required that a high insulating property should beensured between the touch electrode Tx and the routing line TW. Forexample, it is preferable that the first passivation layer PAS1 has athickness of 2,000 Å or more to reduce the electrostatic noise betweenthe touch electrode Tx and the routing line TW. In that case, however,the capacitance between the pixel electrode PXL and the common electrodeCOM are also lowered so that the storage capacitance may be reduced. Asthe result, the high speed touch sensing is not possible.

Further, as shown in FIG. 3, when forming the contact holes TH and WHfor connecting the touch electrode Tx and the routing line TW, thecontact hole may be required to have enough area for ensuring goodcontact. In order to prevent reduction of aperture ratio, it ispreferable that the contact holes TH and WH are disposed as beingoverlapped with the lines or close to the lines. However, in the ultrahigh density structure, the area of the pixel area PA is smaller and theelements are closer, so that it is very hard to ensure the area of thecontact hole for good contact.

As mentioned above, for the in-cell touch type flat panel display,especially for the ultra high density display, the contact holeconnecting the touch electrode and the routing line has the minimum openarea and the minimum disposed area. To do so, it is required to developan in-cell type touch panel embedded flat panel display having differentstructure than the related art.

SUMMARY

In order to overcome the above mentioned drawbacks, the purpose of thepresent disclosure is to provide a display having a touch sensor inwhich the parasitic capacitance between the touch electrode and therouting line is eliminated. Another purpose of the present disclosure isto provide a display having a touch sensor in which the storagecapacitance between the pixel electrode and the common electrode issufficient and the parasitic capacitance between the touch electrode andthe routing line is prevented. Still another purpose of the presentdisclosure is to suggest a display having a touch sensor in which theaperture ratio is not reduced in ultra high density structure byminimizing the area of the contact hole for connecting the touchelectrode and the routing line.

In order to accomplish the above purpose, the present disclosuresuggests a display having a touch sensor comprising: a plurality ofpixel areas disposed in a matrix manner on a substrate; a routing linealong a first direction on the substrate; a first passivation layercovering the routing line; a touch electrode covering the routing lineand corresponding to a grouped pixel areas on the first passivationlayer; a touch contact hole exposing some portions of the routing lineby penetrating the touch electrode and the first passivation layer; asecond passivation layer covering the touch electrode; a passivationcontact hole exposing the touch contact hole and some portions of thetouch electrode around the touch contact hole by penetrating the secondpassivation layer; and a touch terminal connecting the touch electrodeand the routing line on the second passivation layer.

In one embodiment, the display further comprises: a data lineoverlapping with the routing line having a planar layer there-between onthe substrate; a gate line running along a second direction crossingwith the first direction on the substrate; a thin film transistorconnected to the gate line and the data line and disposed in the pixelarea under the planar layer; and a pixel electrode disposed within thepixel area on the second passivation layer, connected to the thin filmtransistor and overlapped with the touch electrode having the secondpassivation layer there-between.

In one embodiment, exposed areas of the routing line by the touchcontact hole and the passivation contact hole are equal to or largerthan 2 μm².

In one embodiment, exposed areas of the routing line by the touchcontact hole and the passivation contact hole are less than 3 times ofexposed areas of the touch electrode by the passivation contact hole.

In one embodiment, the touch contact hole and the passivation contacthole have an asymmetric structure.

In one embodiment, any one of the touch contact hole and the passivationcontact hole has a landscape rectangular shape, and the other has aportrait rectangular shape.

In one embodiment, any one of the touch contact hole and the passivationcontact hole is disposed as being shifted to any one side from theother.

In one embodiment, any one of the touch contact hole and the passivationcontact hole is disposed as being shifted to a side where there is noother contact hole.

The present disclosure suggests flat panel display having a touch sensorin which the parasitic capacitance between the touch electrode and therouting line is reduced so that accuracy sensing performance can beimproved, in the ultra high density display. Further, in the ultra highdensity display, by thinning the insulating layer between the commonelectrode and the pixel electrode, a large amount of the storagecapacitance can be provided. The area of contact holes for connectingthe touch electrode and the routing line can be minimized. Inparticular, the two contact holes for exposing the touch electrode andthe routing line are overlapped in vertical structure. Further, thesecontact holes are asymmetrically overlapped in which the contact holesare disposed as concentrating to where there are less contact holes.Therefore, with the minimized contact hole area, the touch electrode canbe connected to the routing line. In addition, these two contact holescan be formed with one mask process so that the manufacturing tact timecan be reduced and the manufacturing cost can be saved.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 is a plane view illustrating the structure of the touch sensorembedded display according to the related art.

FIG. 2 is a plan view illustrating the enlarged part having two touchelectrodes (Tx) denoted as {circle around (a)} in FIG. 1.

FIG. 3 is a plan view illustrating an enlarged area including twoneighboring pixels denoted as {circle around (b)} in FIG. 2 according tothe related art.

FIG. 4 is a cross section view, along the cutting line IT of FIG. 3,illustrating the structure of the liquid crystal display having the selfcapacitance (type) touch sensor according to the related art.

FIG. 5 is a plan view illustrating a structure of a liquid crystaldisplay having a self capacitance touch sensor according to the firstembodiment of the present disclosure.

FIG. 6 is a cross section view, along the cutting line II-IF of FIG. 5,illustrating the structure of the liquid crystal display having the selfcapacitance touch sensor according to the first embodiment of thepresent disclosure.

FIG. 7 is a plan view illustrating a structure of a liquid crystaldisplay having a self capacitance touch sensor according to the secondembodiment of the present disclosure.

FIG. 8 is a cross section view, along the cutting line III-III′ of FIG.7, illustrating the structure of the liquid crystal display having theself capacitance touch sensor according to the second embodiment of thepresent disclosure.

FIGS. 9A to 9C are plan views illustrating various examples of touchcontact holes for connecting the touch electrode and the routing line ina liquid crystal display having a self capacitance touch sensoraccording to the second embodiment of the present disclosure.

DETAILED DESCRIPTION

Referring to attached figures, we will explain preferred embodiments ofthe present disclosure. Like reference numerals designate like elementsthroughout the detailed description. However, the present disclosure isnot restricted by these embodiments but can be applied to variouschanges or modifications without changing the technical spirit.

First Embodiment

FIGS. 5 and 6 illustrate features of the first embodiment of the presentdisclosure. FIG. 5 is a plan view illustrating a structure of a liquidcrystal display having a self capacitance touch sensor according to thefirst embodiment of the present disclosure. FIG. 6 is a cross sectionview, along the cutting line II-IF of FIG. 5, illustrating the structureof the liquid crystal display having the self capacitance touch sensoraccording to the first embodiment of the present disclosure.

Referring to FIGS. 5 and 6, a liquid crystal display having a selfcapacitance touch sensor according to the first embodiment of thepresent disclosure has a plurality of pixel areas PA disposed in amatrix manner defined by the crossing structure of a plurality of gatelines GL and a plurality of data lines DL on a substrate SUB. In eachpixel area PA, a thin film transistor T, a pixel electrode PXL connectedto the thin film transistor T and a common electrode COM facing with thepixel electrode PXL are disposed.

The thin film transistor T may have the double gate structure in whichthe semiconductor layer is overlapped with the gate line GL twice sothat two channel areas A are formed. On the substrate SUB, a lightshielding layer LS may be formed where the channel area A is disposed.On the light shielding layer LS, a buffer layer BUF is deposited ascovering the whole surface of the substrate SUB. On the buffer layerBUF, a semiconductor layer is disposed where the light shielding layerLS is formed. On the semiconductor layer, a gate line GL and the gateelectrode G are disposed with a gate insulating layer GI.

One side of the semiconductor layer is connected to the date line DL.The semiconductor layer has ‘U’ shape so as to cross the gate line GLtwice. The overlapped portion of the gate line GL with the semiconductorlayer would be the gate electrode G. The portions of the semiconductorlayer overlapped with the gate electrode G would be the channel area A.On the whole surface of the substrate SUB having the gate line GL andthe gate electrode G, an intermediate insulating layer IN is deposited.

On the intermediate insulating layer IN, data line DL is disposed. Oneportion of the data line DL is connected to the one side of thesemiconductor layer. The other side of the semiconductor layer isconnected to the drain electrode D. Here, the source electrode S is notformed separately but is defined as the portion of the data line DLoverlapped with the semiconductor layer. The drain electrode D may beformed separately. Otherwise, one portion of the pixel electrode PXLconnected to the other side of the semiconductor layer may be the drainelectrode D.

On the whole surface of the substrate SUB having the thin filmtransistor T including the gate electrode G, the source electrode S andthe drain electrode D, a planar layer PAC is deposited. On the planarlayer PAC, a routing line TW is disposed. Especially, in order to ensurehigh aperture ratio, it is preferable that the routing line TW isoverlapped with the data line DL. On the whole surface of the substrateSUB having the routing line TW, a first passivation layer PAS1 isdeposited.

One routing line TW is connected to any one touch electrode Tx. Bypatterning the first passivation layer PAS1, a touch contact hole THexposing some portions of any one routing line TW is formed. On thefirst passivation layer PAS1 having the touch contact hole TH, a commonelectrode COM is disposed. In order to be used as the touch electrodeTx, the common electrode COM may be patterned as covering a pluralityneighboring pixel areas PA. Here, the common electrode COM is connectedto the routing line TW through the touch contact hole TH. When thecommon electrode COM works as the touch electrode Tx, the touch sensinginformation can be sent via the routing line TW from the touch electrodeTx. It is preferable that the common electrode COM, also being a touchelectrode Tx, has the open structure not covering the pixel contact holePH exposing the drain electrode D.

On the whole surface of the substrate SUB having the common electrodeCOM, a second passivation layer PAS2 is deposited. Patterning the secondpassivation layer PAS2, the first passivation layer PAS1 and the planarlayer PAC, some portions of the drain electrode D are exposed. On thesecond passivation layer PAS2, a pixel electrode PXL is disposed. Thepixel electrode PXL is connected to the drain electrode D of the thinfilm transistor T through the pixel contact hole PH. Within the pixelarea PA, the pixel electrode PXL is disposed as overlapping the commonelectrode COM with the second passivation layer PAS2 there-between. Astorage capacitance may be formed at the overlapped area between thepixel electrode PXL and the common electrode COM.

In the first embodiment of the present disclosure, the touch terminal TTfor connecting the touch electrode Tx to the routing line TW (describedpreviously with reference to FIG. 3) is not formed, but the touchelectrode Tx is directly connected to the routing line TW. Especially,the routing line TW is formed first, the first passivation layer PAS1 isdeposited thereon. Then, the touch contact hole TH exposing someportions of the routing line TW is formed. Forming the touch electrodeTx on the first passivation layer PAS1, the touch electrode Tx canconnect to the routing line TW through the touch contact hole TH.

For the liquid crystal display embedding the self capacitance touchsensor according to the first embodiment of the present disclosure, thetouch contact hole TH for connecting the touch electrode Tx and therouting line TW can have the reduced area for ensuring good contactproperty. Further, as the touch contact hole TH is formed at the areafor the data line DL, the aperture ratio is not reduced by the touchcontact hole area.

The routing line TW extends along to the second direction, i.e., Y-axis,so it may be overlapped with other touch electrodes Tx arrayed along tothe Y-axis. For example, 2row 1column routing line TW21 is connected tothe 2row 1column touch electrode Tx21, and is overlapped with the othertouch electrodes Tx below the 2row 1column touch electrode Tx21 along tothe Y-axis with the first passivation layer PAS1 there-between.

When any parasitic capacitance between the 2row 1column routing lineTW21 and other touch electrodes Tx is present, the sensing accuracy ofthe touch electrodes Tx may be degraded. Therefore, it is important toprovide high insulating property between the touch electrode Tx and therouting line TW. For example, the first passivation layer PAS1 may havethickness of 2,000 Å or more, so that the electrostatic noise betweenthe touch electrode Tx and the routing line TW can be reduced.

Between the pixel electrode PXL and the common electrode COM, there isthe second passivation layer PAS2 only. Therefore, even though the firstpassivation layer PAS1 is too thick (thicker than 2,000 Å) for highinsulating property, the storage capacitance between the pixel electrodePXL and the common electrode COM is not degraded.

Second Embodiment

FIGS. 7 and 8 illustrate the second embodiment of the presentdisclosure. FIG. 7 is a plan view illustrating a structure of a liquidcrystal display having a self capacitance touch sensor according to thesecond embodiment of the present disclosure. FIG. 8 is a cross sectionview, along the cutting line III-III′ of FIG. 7, illustrating thestructure of the liquid crystal display having the self capacitancetouch sensor according to the second embodiment of the presentdisclosure.

Referring to FIGS. 7 and 8, a liquid crystal display embedding a selfcapacitance touch sensor according to the second embodiment of thepresent disclosure has a plurality of pixel areas PA disposed in amatrix manners defined by the crossing structure of a plurality of gatelines GL and a plurality of data lines DL on a substrate SUB. In eachpixel area PA, a thin film transistor T, a pixel electrode PXL connectedto the thin film transistor T and a common electrode COM facing with thepixel electrode PXL are disposed.

The structure of the thin film transistor may be same as that of thefirst embodiment. Therefore, corresponding explanation may not beduplicated.

On the whole surface of the substrate SUB having the thin filmtransistor T including the gate electrode G, the source electrode S, andthe drain electrode D, a planar layer PAC is deposited. On the planarlayer PAC, a routing line TW is disposed. Especially, in order to ensurehigh aperture ratio, it is preferable that the routing line TW isoverlapped with the data line DL. On the whole surface of the substrateSUB having the routing line TW, a first passivation layer PAS1 isdeposited.

On the first passivation layer PAS1, a common electrode COM is disposed.In order to be used as the touch electrode Tx, the common electrode COMmay be patterned as covering a plurality neighboring pixel areas PA.Here, the common electrode COM may be overlapped with the routing lineTW. Further, it is preferable that the common electrode COM, also beinga touch electrode Tx, has the open structure not covering the pixelcontact hole PH exposing the drain electrode D. For example, it ispreferable that a common hole CMH exposing circumstances of the pixelcontact hole PH is formed, when forming the common electrode COM. Anyone routing line TW should be connected to any one touch electrode Tx.Here, at the mask process for patterning the common electrode COM, morepatterning the overlapped area between the common electrode COM and therouting line TW, the touch contact hole TH may be formed as exposingsome portions of the routing line TW. The touch contact hole TH exposessome portions of the routing line TW by penetrating the common electrodeCOM and the first passivation layer PAS1.

On the whole surface of the substrate SUB having the common electrodeCOM, a second passivation layer PAS2 is deposited. Patterning the secondpassivation layer PAS2, the first passivation layer PAS1 and the planarlayer PAC, a pixel contact hole PH exposing some portions of the drainelectrode D is formed. Here, by patterning the second passivation layerPAS2 covering the touch contact hole TH, a passivation contact hole PAHexposing the touch contact hole TH is formed. The passivation contacthole PAH may be patterned as having larger area than the touch contacthole TH or as having an asymmetric shape to expose some portions of thecommon electrode COM surrounding the touch contact hole TH.

On the second passivation layer PAS2, a pixel electrode PXL is disposed.The pixel electrode PXL connects to the drain electrode D of the thinfilm transistor T through the pixel contact hole PH. Within the pixelarea PA, the pixel electrode PXL is disposed as overlapping the commonelectrode COM with the second passivation layer PAS2 there-between. Astorage capacitance may be formed at the overlapped area between thepixel electrode PXL and the common electrode COM. Here, a touch terminalTT is further formed with the same material of the pixel electrode PXLbut it is separated from the pixel electrode PXL. The touch terminal TTconnects the touch electrode Tx exposed through the passivation contacthole PAH and the routing line TW exposed through the touch contact holeTH. When using as the touch electrode Tx, the common electrode COM cansend the sensing information via the routing line TW.

For the liquid crystal display embedding the self capacitance touchsensor according to the second embodiment of the present disclosure, thetouch contact hole TH for connecting the touch electrode Tx and therouting line TW can have the minimized area for providing good contactproperty. Further, as the touch contact hole TH and the touch terminalTT are formed at the area for the data line DL, the aperture ratio isnot reduced by these areas.

The routing line TW extends along to the second direction, i.e., Y-axis,so it may be overlapped with other touch electrodes Tx arrayed along tothe Y-axis. For example, 2row 1column routing line TW21 is connected tothe 2row 1column touch electrode Tx21, and is overlapped with the othertouch electrodes Tx below the 2row 1column touch electrode Tx21 along tothe Y-axis with the first passivation layer PAS1 there-between.

When any parasitic capacitance between the 2row 1column routing lineTW21 and other touch electrodes Tx is occurred, the sensing accuracy ofthe touch electrodes Tx may be degraded. Therefore, it is important toprovide high insulating property between the touch electrode Tx and therouting line TW. For example, the first passivation layer PAS1 may havethickness of 2,000 Å or more, so that the electrostatic noise betweenthe touch electrode Tx and the routing line TW can be reduced.

Between the pixel electrode PXL and the common electrode COM, there isthe second passivation layer PAS2 only. Therefore, even though the firstpassivation layer PAS1 is too thick (thicker than 2,000 Å) for highinsulating property, the storage capacitance between the pixel electrodePXL and the common electrode COM is not degraded.

Further, in the second embodiment, the touch contact hole TH and thepassivation contact hole PAH for connecting the touch electrode Tx andthe routing line TW are formed without additional mask processes. Bycomparing with the first embodiment, the manufacturing process can bemore simplified.

In detail, the first embodiment requires a first mask process forforming the routing line TW, a second mask process for forming the touchcontact hole TH at the first passivation layer PAS1, a third maskprocess for forming the common electrode COM, a fourth mask process forforming the pixel contact hole PH at the second passivation layer PAS2,and a fifth mask process for forming the pixel electrode PXL on thesecond passivation layer PAS2. That is, from the step for forming therouting line TW to the step for forming the touch electrode Tx, thefirst embodiment requires at least 5 mask processes.

In the interim, the second embodiment requires a first mask process forforming the routing line TW, a second mask process for forming thecommon electrode COM and the touch contact hole TH on the firstpassivation layer PAS1, a third mask process for forming the pixelcontact hole PH and the passivation contact hole PAH at the secondpassivation layer PAS2, and a fourth mask process for forming the pixelelectrode PXL and the touch terminal TT on the second passivation layerPAS2. That is, from the step for forming the routing line TW to the stepfor forming the touch electrode Tx, the second embodiment requires 4mask processes.

In the first embodiment, the contact hole for connecting the touchelectrode Tx and the routing line TW is the touch contact hole TH.However, in the second embodiment, there are two contact holes forconnecting the touch electrode Tx and the routing line TW, thepassivation contact hole PAH and the touch contact hole TH. As these twocontact holes PAH and TH are overlapped in vertical structure, the areafor the contact holes can be minimized. This contact hole structure canbe applied to the ultra high density flat panel display.

In the market for the flat panel display, the resolution density isgetting higher, from the high density (or HD), the full high density (orFHD), the ultra high density (or UHD) to the ultra plus high density(UHD+, over 5K). Therefore, the space for embedding the touch sensor isgetting smaller. As mentioned above, the space for disposing the contacthole connecting the touch electrode Tx and the routing line TW isgetting smaller or narrower.

In order to overcome these restrictions, in the second embodiment of thepresent disclosure, the passivation contact hole PAH and the touchcontact hole TH are formed and/or disposed in an asymmetric structure.Doing so, it is possible to suggest an ultra high density flat paneldisplay (over 4K) embedding the touch sensor. FIGS. 9A to 9C illustratethe asymmetric structure of the contact holes. FIGS. 9A to 9C are planeviews illustrating various examples of touch contact holes forconnecting the touch electrode and the routing line in a liquid crystaldisplay having a self capacitance touch sensor according to the secondembodiment of the present disclosure.

At first, FIG. 9A is a plane view illustrating the contact holes havingan asymmetric structure. As shown in FIG. 9A, in order to expose therouting line TW, a touch contact hole TH is formed by patterning thetouch electrode Tx21 and the first passivation layer PAS1 there-under.Here, the touch contact hole TH may have any one shape of an ellipse, acircle, a perfect square, a lozenge, a rectangle and so on, properly toexpose some portions of the routing line TW. Here, in convenience, arectangular shaped contact hole is presented as an example. In FIG. 9A,the hatch pattern of 45° angle line means the some portions of therouting line TW exposed by the touch contact hole TH.

By depositing the second passivation layer PAS2 covering the touchelectrode Tx and then etching some portions of the second passivationlayer PAS2 covering the touch contact hole TH, the passivation contacthole PAH is formed as exposing the touch contact hole TH and someportions of the touch electrode Tx surrounding the touch contact holeTH. In FIG. 9A, the hatch pattern of 135° angle line means the areasexposed through the passivation contact hole PAH. That is, the areasmarked only by the 135° angle line means the some portions of the touchelectrode Tx surrounding the touch contact hole TH and exposed by thepassivation contact hole PAH.

On the second passivation layer PAS2, the touch terminal TT is formed ashaving larger size than the touch contact hole TH. The touch terminal TTmay cover all areas marked by both hatch patterns. That is, someportions of the routing line TW marked by the hatch pattern of 45° angleline and some portions of the touch electrode Tx marked by the hatchpattern of 135° angle line are connected by the touch terminal TT.

In FIG. 9A, the touch contact hole TH and the passivation contact holePAH have the same shape and they are disposed in a symmetric structure.Therefore, when other contact holes may be disposed near them, it isrequired that the sizes of the touch contact hole TH and the passivationcontact hole PAH may be smaller. When the sizes of the touch contacthole TH and the passivation contact hole PAH are too small, the areasfor exposing the routing line TW and the touch electrode Tx are smaller,too. As the result, the contact of the touch terminal TT between therouting line TW and the touch electrode Tx may not have good property.

In some embodiments, the contact holes have an asymmetric structure. Inorder to provide enough contact area when other contact holes aredisposed around any one contact hole in the ultra high density flatpanel display, it is preferable that the contact holes have theasymmetry structure. For example, as shown in FIG. 9B, the touch contacthole TH is formed as exposing some portions of the routing line TW bypatterning the touch electrode Tx21 and the first passivation layer PAS1there-under. Like the FIG. 9A, the touch contact hole TH may have anyone shape of an ellipse, a circle, a square, a lozenge, a rectangle andso on, properly to expose some portions of the routing line TW. Further,in convenience for comparing with FIG. 9A, the touch contact hole TH hasthe rectangular shape. In FIG. 9B, the hatch pattern of 45° angle lineindicate portions of the routing line TW exposed by the touch contacthole TH.

By depositing the second passivation layer PAS2 covering the touchelectrode Tx and then etching some portions of the second passivationlayer PAS2 covering the touch contact hole TH, the passivation contacthole PAH is formed as exposing some of the touch contact hole TH andsome portions of the touch electrode Tx surrounding the touch contacthole TH. Especially, the passivation contact hole PAH has a differentshape from the touch contact hole TH. For example, the passivationcontact hole PAH may have a lozenge shape. When other contact holes aredisposed at right and/or left sides of the touch contact hole TH, thetouch contact hole TH may have the vertically long lozenge shape inwhich the Y-axis line would be longer and X-axis would be shorter.

In FIG. 9B, the hatch pattern of 135° angle line means the areas exposedthrough the passivation contact hole PAH. As shown in FIG. 9B, theexposed portions of the touch electrode Tx by the passivation contacthole PAH are the upper portions and lower portions from the touchcontact hole TH. In other words, the areas marked only by 135° angleline indicate portions of the touch electrode Tx surrounding the touchcontact hole TH and exposed by the passivation contact hole PAH.

On the second passivation layer PAS2, the touch terminal TT is formed ashaving larger size than the touch contact hole TH. The touch terminal TTmay cover all areas marked by both hatch patterns. That is, someportions of the routing line TW marked by the hatch pattern of 45° angleline and some portions of the touch electrode Tx marked by the hatchpattern of 135° angle line are connected by the touch terminal TT.

In the asymmetric structure like in FIG. 9B, the passivation contacthole PAH and the touch contact hole TH may have different shapes.Further, it is preferable that it may have longer axis to avoid meetingwith other contact holes.

FIG. 9C shows another example for contact holes having an asymmetricstructure. The contact hole structure as shown in FIG. 9C can be appliedwhen any other contact holes are disposed around the touch contact holein any direction. Referring to FIG. 9C, the touch contact hole TH isformed as exposing some portions of the routing line TW by patterningthe touch electrode Tx21 and the first passivation layer PAS1there-under. In comparison with FIG. 9A, the touch contact hole TH ofFIG. 9B has a rectangular shape. In FIG. 9C, the hatch pattern of 45°angle line means the some portions of the routing line TW exposed by thetouch contact hole TH.

By depositing the second passivation layer PAS2 covering the touchelectrode Tx and then etching some portions of the second passivationlayer PAS2 covering the touch contact hole TH, the passivation contacthole PAH is formed as exposing some of the touch contact hole TH andsome portions of the touch electrode Tx surrounding the touch contacthole TH. In particular, the passivation contact hole PAH has a differentshape from the touch contact hole TH. Further, the disposed structure isalso asymmetric. For example, the passivation contact hole PAH hasrectangular shape of which long axis is different from the long axis ofthe touch contact hole TH. When the touch contact hole TH is thelandscape rectangular shape and other contact holes are disposed atright and/or left sides of the touch contact hole TH, the passivationcontact hole PAH may be the portrait rectangular shape. When still othercontact holes are disposed above the touch contact hole TH, then thepassivation contact hole PAH may have much longer portrait rectangularshape.

In FIG. 9C, the hatch pattern of 135° angle line indicate the areasexposed through the passivation contact hole PAH. As shown in FIG. 9C,the exposed portions of the touch electrode Tx by the passivationcontact hole PAH are the lower portions from the touch contact hole TH.In other words, the areas marked only by 135° angle line means the someportions of the touch electrode Tx disposed below the touch contact holeTH and exposed by the passivation contact hole PAH.

On the second passivation layer PAS2, the touch terminal TT is formed ashaving larger size than the touch contact hole TH and the passivationcontact hole PAH. The touch terminal TT may cover all areas marked byboth hatch patterns. That is, some portions of the routing line TWmarked by the hatch pattern of 45° angle line and some portions of thetouch electrode Tx marked by the hatch pattern of 135° angle line areconnected by the touch terminal TT.

In the asymmetric structure like FIG. 9C, the passivation contact holePAH and the touch contact hole TH may have different shapes. Further, itis preferable that the overlapped two contact holes may have longer axisto avoid meeting with other contact holes, or any one of the twooverlapped contact holes may be disposed as shifted one side. In thepresent disclosure, the asymmetric structure of the verticallyoverlapped two contact holes means that two contact holes have differentshapes and/or that two contact holes are disposed in a manner that thecenter point of any one contact hole is not aligned on the center pointof the other contact hole.

Even though the overlapped two contact holes are disposed in anasymmetric structure, the exposed areas of the routing line TW by thetouch contact hole TH and the exposed areas of the touch electrode Tx bythe passivation contact hole PAH may be enough to provide good contactproperty. It is preferable that the areas of the exposed portions aresatisfied following conditions.

At first, it is preferable that the overlapped open area of thepassivation contact hole PAH and the touch contact hole TH is equal orlarger than 2 μm². In the cases of the FIGS. 9B and 9C, the passivationcontact hole PAH exposes all portions of the routing lines TW exposed bythe touch contact hole TH. Therefore, the overlapped open area is equalto the exposed area of the routing line TW. When it is required that thesize of the passivation contact hole PAH, the passivation contact holePAH may expose some of the exposed routing line TW by the touch contacthole TH. At any case, it is preferable that the finally opened areas ofthe exposed routing line TW by the passivation contact hole PAH and thetouch contact hole TH are larger than 2 μm². If the finally opened areasof the exposed routing line TW are smaller than 2 μm², the contactresistance may be increased so that the touch information detected bythe touch electrode Tx may not be sent via the routing line TW,properly.

Finally, it is preferable that the overlapped open area of thepassivation contact hole PAH and the touch contact hole TH is less than3 times of the unoverlapped opened area of the passivation contact holePAH with the touch contact hole TH. The unoverlapped opened area of thepassivation contact hole PAH with the touch contact hole TH means thearea of the exposed touch electrode Tx by the passivation contact holePAH. Therefore, the area of the exposed routing line TW by all of thepassivation contact hole PAH and the touch contact hole TH, at least, isthe same with the area of the exposed touch electrode Tx by thepassivation contact hole PAH. At most, the area of the exposed routingline TW by all of the passivation contact hole PAH and the touch contacthole TH does not need to be larger than 3 times of the exposed touchelectrode Tx by the passivation contact hole PAH. Even it is larger than3 times, the contact resistance is not lowered, but it occupies too mucharea so that it may reduce the aperture ratio.

In some embodiments, the touch contact hole TH has rectangular shape andthe passivation contact hole PAH has an asymmetric shape or disposedwith the center is shifted or offset to one direction. This is caused bythat the touch contact hole TH is formed former than the passivationcontact hole PAH. If required, the shapes of these two contact holes maybe exchanged. Further, the touch contact hole TH may be shifted from thepassivation contact hole PAH to any side where there are no othercontact holes.

While the embodiment of the present invention has been described indetail with reference to the drawings, it will be understood by thoseskilled in the art that the invention can be implemented in otherspecific forms without changing the technical spirit or essentialfeatures of the invention. Therefore, it should be noted that theforgoing embodiments are merely illustrative in all aspects and are notto be construed as limiting the invention. The scope of the invention isdefined by the appended claims rather than the detailed description ofthe invention. All changes or modifications or their equivalents madewithin the meanings and scope of the claims should be construed asfalling within the scope of the invention.

What is claimed is:
 1. A display comprising: a plurality of pixel areasdisposed in a matrix manner on a substrate; a routing line running to afirst direction on the substrate; a first passivation layer covering therouting line; a touch electrode covering the routing line andcorresponding to a grouped pixel areas on the first passivation layer; atouch contact hole exposing some portions of the routing line bypenetrating the touch electrode and the first passivation layer; asecond passivation layer covering the touch electrode; a passivationcontact hole exposing the touch contact hole and some portions of thetouch electrode around the touch contact hole by penetrating the secondpassivation layer; and a touch terminal connecting the touch electrodeand the routing line on the second passivation layer.
 2. The displayaccording to claim 1, further comprising: a data line overlapping withthe routing line having a planar layer there-between on the substrate; agate line running to a second direction crossing with the firstdirection on the substrate; a thin film transistor connected to the gateline and the data line and disposed in a pixel area under the planarlayer; and a pixel electrode disposed within the pixel area on thesecond passivation layer, connected to the thin film transistor andoverlapped with the touch electrode having the second passivation layerthere-between.
 3. The display according to claim 1, wherein exposedareas of the routing line by the touch contact hole and the passivationcontact hole are equal to or larger than 2 μm².
 4. The display accordingto claim 1, wherein exposed areas of the routing line by the touchcontact hole and the passivation contact hole are less than 3 times ofexposed areas of the touch electrode by the passivation contact hole. 5.The display according to claim 1, wherein the touch contact hole and thepassivation contact hole have an asymmetric structure.
 6. The displayaccording to claim 5, wherein any one of the touch contact hole and thepassivation contact hole has a landscape rectangular shape, and theother has a portrait rectangular shape.
 7. The display according toclaim 6, wherein any one of the touch contact hole and the passivationcontact hole is disposed as being shifted to any one side from theother.
 8. The display according to claim 6, wherein any one of the touchcontact hole and the passivation contact hole is disposed as beingshifted to a side where there is no other contact hole.